CVE-2021-27876: Veritas Backup Exec Agent File Access Vulnerability
Vulnerability summary
CVE-2021-27876 is a high (CVSS 8.1) vulnerability in Veritas Backup Exec Agent. It is known to be exploited: CISA lists it, first on 07-04-2023. It has been used in ransomware campaigns. EPSS estimates a 13.52% chance of exploitation in the next 30 days, higher than 96.4% of scored vulnerabilities. 2 public exploits are recorded.
Timeline
- 01-03-2021PublishedVulnerability first disclosed.
- 07-04-2023Added to CISA KEVVeritas Backup Exec Agent File Access Vulnerability
- 28-04-2023CISA remediation dueApply updates per vendor instructions.
- 21-10-2025Last modifiedVulnerability information updated.
Description
An issue was discovered in Veritas Backup Exec before 21.2. The communication between a client and an Agent requires successful authentication, which is typically completed over a secure TLS communication. However, due to a vulnerability in the SHA Authentication scheme, an attacker is able to gain unauthorized access and complete the authentication process. Subsequently, the client can execute data management protocol commands on the authenticated connection. By using crafted input parameters in one of these commands, an attacker can access an arbitrary file on the system using System privileges.
CVSS metrics
3 scores · 2 sources · 2 versions- NVDNIST8.1HighCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
EPSS trend
Probability
13.52%
Chance of exploitation in the next 30 days
Percentile
96%
Versus all other CVEs
30-day change
0.00 pp
From 13.52% on 18-09-2026
Known exploited
Compare KEV catalogs
CISA KEVListed- Added
- 07-04-2023
- Federal due date
- 28-04-2023
CISA required action
Apply updates per vendor instructions. www.veritas.com/support/en_US/security/VTS21-001 nvd.nist.gov/vuln/detail/CVE-2021-27876
Public exploits
2 foundExploit Reference (packetstormsecurity.com)
Maturity: unknown
Veritas Backup Exec Agent Remote Code Execution
exploit/multi/veritas/beagent_sha_auth_rce
Maturity: weaponized
Weaknesses
CWE · root causeNo weakness data has been published for this record.
Affected systems
Veritas1 product
- backup_exec< 21.2
1 vendor · 1 product
References
3 links- packetstormsecurity.com/files/168506/Veritas-Backup-Exec-Agent-Remote-Code-Execution.htmlX Refsource MISCExploitThird Party AdvisoryVDB Entry
- www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-27876Government ResourceUS Government Resource